The Domestic Master Contractor (DMC) of the HIV Vaccine Efficacy Trials Network (HIVNET) shall be responsible for three technical tasks (Tasks I, II and III) and two administrative tasks (Task IV and V): The technical tasks are: I) Core Support for Efficacy Trials Preparedness: 1) provide operational and technical support to the Advisory Working Group and the Steering Group of the HIVNET, and 2) develop and maintain a network of field sites capable of conducting efficacy trials of HIV vaccines and other biomedical interventions. The DMC shall have sufficient core administrative and technical capacity to support preparatory baseline/feasibility studies requested by the NIAID. II) Award of Subcontracts for Preparatory Baseline/Feasibility Studies: The DMC shall solicit and award subcontracts for continuation of preparatory baseline/feasibility studies that are currently supported by the NIAID and shall solicit and award subcontracts for up to 10 new preparatory/feasibility studies as requested by the NIAID over the course of the contract. III) Support of Efficacy Trials: At the request of the NIAID, the DMC shall solicit and award subcontracts for trial sites and provide administrative and technical support for the implementation of the efficacy trials. In implementing the efficacy trials, the DMC shall coordinate with Statistical and Clinical Coordinating Center Contractor, the Repository Contractor, and Central Laboratory Contractor of the HIVNET. The administrative tasks are: IV) Subcontract implementations and administration V) Transition Plan Development